She joined the Social Democratic Party (Sozialdemokratische Partei Deutschlands / SPD) in 1906, and within it was responsible for "Women work" in Berlin between 1907 and 1916.
When the USPD itself split in 1920, Arendsee was a strong advocate for the political regrouping which led to the creation of the Communist Party, of which she was a member from 1920.
Martha Arendsee's name was on the USPD candidate list, positioned high enough up for her to become one of the party's 24 members in 401 seat assembly.
She continued to apply herself to work with the Workers International Relief organisation, however, and is listed as a member of its national executive between 1931 and 1935[2] The political backdrop changed dramatically in January 1933 when the Nazis took power and converted Germany into a one-party dictatorship.
Arendsee was arrested in April 1933 and held in "protective custody" at the Barnimstrasse women's prison in Berlin in till September 1933.
[6] In Moscow she undertook a succession of party and welfare related jobs, working at one stage in the socio-economic department of Profintern.
[2] 1941 was the year in which the non-aggression pact with Nazi Germany broke down when the German army invaded the Soviet Union.
[2] In 1943 she was one of the co-founders - according to one source the only female among them - of the Soviet sponsored National Committee for a Free Germany (Nationalkomitee Freies Deutschland / NKVD), an organisation for which she worked till 1945.
[2] Between 1945 and 1948 she headed up the Social Policy department of the Trades Union Federation (Freier Deutscher Gewerkschaftsbund / FDGB).
Three years later, in 1978, a few months after celebrations marking the twenty-fifth anniversary of her death, a street in Berlin-Marzahn - then a large and prestigious newly built city district - was named after her.